As you probably know, video game prices are not always indicative of the rarity of a game. It is based on may factors like interest in the genre or characters in the game. In this case, a lot of people just want this game because it is a good game (regardless of how bad the controls are), not great, but good.
Also, more importantly, it is based on a cartoon series that people like as well, so you are going to have collectors interested in Futurama wanting the game as well as PS2 collectors and game collectors. Generally speaking, the cartoon series had a cult following and now it is cancelled (in 2013 I believe) and will probably never be available again, so anything Futurama instantly becomes a kind of collectible item that represents a certain time in pop culture. This is true of many video games...it's just the way it goes with this sort of thing. similarly, with Star Trek video games and Star Wars video games, prices are somewhat inflated because of the fact that not only gamers want the games, but also Star Wars and Star Trek collectors want them too...demand even extends to people that just collect movie memorabilia or lucasarts memorabilia, or 80's and 90's memorabilia, or toys, or whatever else....the list goes on and on
You are competing with many types of collectors and gamers with many interests....with a finite supply of these older items, it is inevitable that sometime prices of games will seem over-inflated, but it is not unreasonable as the marketplace eventually dictates the price.
the game is indeed worth $70-100US according to price charting:
https://www.pricecharting.com/game/playstation-2/futurama
